Preheat oven to 400°F. Spray a large baking pan with non-stick cooking spray or foil and set aside.
To make the seasoning, combine the chili powder, cumin, sea salt and black pepper. Set aside.
Spread the sliced bell peppers, onion and chicken on the prepared baking sheet. Add the minced garlic then drizzle the olive oil over everything. Toss to evenly coat.
Top with chicken strips then sprinkle garlic and seasoning evenly over chicken strips.
Roast in the preheated oven, stirring halfway through, until the veggies are tender and chicken is cooked, 20-25 minutes total. Once the chicken is cooked through, turn on the broiler and allow to cook for 2-3 minutes until peppers start to get crispy on the edges.
Wrap tortillas tightly in foil and warm in oven during last 5 minutes of fajita filling cooking.
Drizzle lime juice evenly over the top of the pan and sprinkle with chopped cilantro.
Serve warm with tortillas tortillas and optional toppings.